Method for coating a flexible support with a silicone composition
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Solution Overview
Problem
The existing coating techniques for liquid silicone compositions on flexible supports using crosslinking by condensation reactions face challenges such as 'blocking' issues during storage, toxicity concerns with tin-based catalysts, and the difficulty in achieving transparent or translucent solid silicone coatings.
Innovation Solution
A process involving a silicone composition crosslinkable by condensation reactions, using a magnesium complex with carboxylate ligands as a catalyst, which allows for crosslinking at ambient temperatures without tin-based catalysts, thereby preventing 'blocking' and enabling the production of transparent or translucent solid silicone elastomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tin-based catalysts are used for condensation crosslinking of silicone compositions, then crosslinking efficiency is improved, but toxicity and harmful effects increase
Solution Approach 1:
The patent replaces expensive and toxic tin-based catalysts with zinc-based catalysts that are less toxic and more environmentally friendly. The zinc catalyst system provides sufficient crosslinking efficiency without the harmful effects of tin compounds, effectively substituting a harmful substance with a safer alternative while maintaining functional performance.
Solution Approach 2:
The patent modifies the catalyst system by changing from tin-based to zinc-based catalysts and adjusts the crosslinking conditions (temperature, humidity control) to optimize performance. This parameter change eliminates toxicity while maintaining or improving crosslinking efficiency through controlled environmental conditions during curing.
2Productivity
If high temperature ovens are used for crosslinking silicone compositions, then crosslinking speed is improved, but energy consumption increases and damage to temperature-sensitive flexible supports occurs
Solution Approach 1:
The patent changes the crosslinking parameters by using ambient temperature and controlled humidity instead of high temperature heating. This allows crosslinking to proceed at lower temperatures, reducing energy consumption and preventing damage to temperature-sensitive flexible supports while maintaining adequate crosslinking speed through humidity control.
Solution Approach 2:
The patent replaces thermal energy input (heating) with chemical reaction control through humidity management. Instead of using high temperature ovens to drive crosslinking, the system uses controlled humidity environments to activate and accelerate the condensation reaction, substituting thermal processing with moisture-controlled chemical processing.
3Temperature
If conventional condensation catalysts are used, then crosslinking can occur at room temperature, but blocking issues occur during storage
Solution Approach 1:
The patent separates the crosslinking activation mechanism from the storage stability requirement by using a dual-component system where the zinc catalyst and silicone composition can be stored separately or together without premature reaction. The catalyst activates crosslinking only when exposed to humidity, allowing stable storage while enabling room temperature crosslinking when needed.
Solution Approach 2:
The patent prepares the silicone composition with pre-hydrolyzed silane groups that remain stable during storage but become active for crosslinking when exposed to humidity. This preliminary preparation allows the material to be stored without blocking while ready to crosslink at room temperature upon exposure to moisture, separating storage stability from crosslinking activation.
4Productivity
If rapid coating speeds are used, then productivity is improved, but blocking issues during storage worsen
Solution Approach 1:
The patent extracts the crosslinking activation trigger from the coating application process itself, allowing rapid coating without immediate crosslinking. The zinc catalyst system enables the coated material to remain stable during storage and handling, preventing blocking even when coating speeds are high, by requiring humidity exposure to initiate crosslinking.
Solution Approach 2:
The patent applies the silicone composition to the flexible support in a pre-hydrolyzed but non-crosslinked state, allowing rapid coating and immediate storage without blocking. The crosslinking action is postponed until humidity exposure, enabling high productivity through fast coating while maintaining storage stability through delayed crosslinking activation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively prevents 'blocking' during storage and produces transparent or translucent solid silicone coatings on flexible supports, eliminating the need for toxic tin-based catalysts and ensuring stable, non-stick, and water-repellent properties.
Implementation Method 1
using a magnesium complex with carboxylate ligands as a catalyst, which allows for crosslinking at ambient temperatures
Implementation Method 2
crosslinking by condensation reactions
Implementation Method 3
accelerate the hydrolysis of the reactive functions
Data Source
AI summary
The present invention concerns a method for coating a textile material with a silicone elastomer composition crosslinkable by condensation reactions, to produce a solid silicone elastomer, optionally in a thin layer, on a flexible support that can be made from a textile material, paper, polyvinyl chloride, polyester, polypropylene, polyamide, polyethylene, polyurethane, non-woven glass fibre fabric or polyethylene terephthalate.